meadows and environmental conditions at a particular time and place. choices regarding sub-sampling, sample size, and the number of replicates need to be defined and supported in the sampling plan, as discussed earlier. Such surveys are extremely valuable, but their value is usually known only after the data are needed for a specific purpose. for others researchers, the existence of data describing a seagrass meadow with certain, specific characteristics can help them explore patterns in the data and formulate ideas regarding the nature of these systems (induction). to provide quantitative data on the natural temporal variability of seagrass populations, a critical need for detecting change, baseline studies must be collected on more than one occasion(ward and jacoby 1992, kirkman 1996)